1. Field of the Invention
This invention relates generally to printers that are adapted for use with portable computers and, more particularly, to compact printers that are adapted to receive and carry portable teletransaction computers or data terminals.
2. Description of the Related Art
Compact printers adapted to receive and carry portable computers or data terminals typically include a housing and associated carrying handle, a printer mechanism with a platen, a printing element and paper supply, a cradle and associated connector for receiving a portable computer, and a power supply, batteries and charging cord. A portable computer can be placed into the cradle of the printer and a connector of the computer can be urged into mating engagement with the connector of the printer. Data that is stored in the portable computer then can be printed out in readable format on the paper.
Compact printers of this kind sometimes will be used to carry a portable computer at a work site. While information is being entered into the computer, the printer is simultaneously providing a readable print-out of the entered data. At other times, data will be entered into the computer prior to its being installed in the printer, and a readable copy of the previously entered data will be produced at a later time. For example, portable computers and compact printers often will be used by delivery personnel to record data relating to successive deliveries and pickups and provide a printout or invoice for each delivery or pickup. The printer must be capable of being transported to work sites where it is needed and also capable of enduring harsh environmental conditions. Therefore, it is very important that the printer have small size, light weight, and good durability. If the portable computer and printer ordinarily will remain connected together, it is preferable that the printer provide some degree of external protection for the computer.
The mating engagement of the printer connector and the portable computer connector must be secure and positive, and must stand up to thousands of coupling cycles without deterioration. One of the two connectors typically includes many small, parallel metal connecting pins that are received into complementary conductive connecting bores in the other connector. Unfortunately, in engaging the two connectors, a user is apt to move the portable computer in a rotating or swinging motion as the computer is brought down into the receiving cradle. The swinging motion can cause the parallel connecting pins of one connector to hit the surface of the other connector or to confront the bores at an angle rather than axially, bending the pins or creating unwanted free play in the pins. Ultimately, the bending or free play can result in pins breaking off.
When connecting pins work loose or break off, the connector must be replaced. It is not unusual for such connectors to require replacement after merely 1000 to 2000 coupling cycles, which can be less than one year of service. The replacement cost of the connector itself is an unwanted expense, but the repair also results in the printer being unavailable.
In operation, some compact printers do not easily accommodate portable computers of various shapes and configurations and do not securely hold the computer in place. In addition, some printers can leave the computer relatively exposed, so that objects can fall against the computer or adverse environmental conditions can affect the computer. In any of these situations, the computer can become damaged and require extensive repair. Further, some printers fail to protect the printer mechanism and control electronics from damage due to environmental factors like rain and snow or falling objects. Yet further, some printers are not convenient to use, either because they do not easily accommodate different portable computers and different configurations, or because their layout makes it awkward to use the printer and computer together.
From the discussion above, it should be apparent that there is a need for a portable compact printer that securely engages with a portable computer, that protects the mating electrical connectors from excessive wear and damage, and that is convenient to use. The present invention satisfies this need.